Plate-shaped electric connectors mounted on boards are conventionally used as connectors to connect flexible circuit boards to the circuit boards, or the like.
As this type of electric connectors, for example, there is known a connector in which contact trains (a plurality of connection terminals) are provided in an opposite manner in each of a socket to be mounted on a circuit board and a plug concave-convex engaged therewith, on both sides in respective lateral directions. The socket includes a middle ground connection fitting that extends between the contact trains in train directions (longitudinal direction of the socket), and end connection members provided on both ends for continuity between the middle ground connection fitting and the circuit board. The plug includes a board connection member that can be engaged with both the end connection members of the socket to come into contact therewith from the lateral direction, and can be connected to a ground portion of the flexible circuit board (for example, see Patent Literature 1).